How many times, whilst diving, have you seen the most exciting, unusual or incredible critter and wanted to show it to your buddies? You have finally managed to grab their attention and pointed at the critter, only for them to look in the direction of your pointed finger and then stare blankly back at you. You point closer, you waggle your hand and still they don’t see it, by which time, the critter has disappeared, your buddies have given up the search, shrugged their shoulders and swum off.